Garmin GTX 335 w GPS User manual

190-00734-17 March 2017 Revision 1
GTX 335 w/GPS
Installation Guidance
From STC SA01714WI


190-00734-17 GTX 335 w/GPS Installation Guidance
Rev. 1 Page A
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RECORD OF REVISIONS
Revision Rev Date Description
1 03/29/17 Initial Release.

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INFORMATION SUBJECT TO EXPORT CONTROL LAWS
This document may contain information which is subject to the Export Administration Regulations (EAR)
issued by the United States Department of Commerce (15 CFR, Chapter VII, Subchapter C) and which
may not be exported, released, or disclosed to foreign nationals inside or outside of the United States
without first obtaining an export license.
Information in this document can change without notice. Go to Garmin’s website www.garmin.com for
updates and supplemental information about the operation of Garmin units.
DEFINITIONS OF WARNINGS, CAUTIONS, AND NOTES
WARNING
A Warning means that injury or death is possible if the instructions are not
followed.
CAUTION
A Caution means that damage to the equipment is possible.
NOTE
A Note provides more information.

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WARNING
This product, its packaging, and its components contain chemicals known to the State of
California to cause cancer, birth defects, or reproductive harm. This notice is being
provided in accordance with California's Proposition 65. If you have any questions or
would like more information, please refer to our website at
www.garmin.com/prop65.
WARNING
Perchlorate Material – special handling may apply.
Refer to www.dtsc.ca.gov/hazardouswaste/perchlorate.
CAUTION
The GTX 335 has a special anti-reflective coated display that is sensitive to waxes and
abrasive cleaners. CLEANERS THAT HAVE
AMMONIA WILL CAUSE DAMAGE TO THE
ANTI-REFLECTIVE COATING. Clean the display with a clean, lint-free cloth and a
cleaner that is safe for anti-reflective coatings.
NOTE
All screen shots used in this document are current at the time of publication. Screen shots
are intended to provide visual reference only. All information depicted in screen shots, such
as software file names, versions, and part numbers, is subject to change and may not
be up
to date.

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TABLE OF CONTENTS
1 GENERAL DESCRIPTION ................................................................................................................1-1
1.1 Introduction ...................................................................................................................................1-2
1.2 Terminology ..................................................................................................................................1-2
1.3 Scope .............................................................................................................................................1-4
1.4 System Overview ..........................................................................................................................1-5
1.5 System Installation ......................................................................................................................1-11
1.6 Technical Specifications .............................................................................................................1-12
1.7 Reference Documentation ...........................................................................................................1-12
1.8 STC Permission ...........................................................................................................................1-13
2 LIMITATIONS .....................................................................................................................................2-1
2.1 Operational Limitations ................................................................................................................2-1
2.2 Installation Limitations .................................................................................................................2-1
3 INSTALLATION OVERVIEW ..........................................................................................................3-1
3.1 Pre-Installation Information ..........................................................................................................3-2
3.2 Garmin Available Installation Materials .......................................................................................3-3
3.3 Installation Materials Not Supplied ..............................................................................................3-3
3.4 Installation Considerations ............................................................................................................3-4
3.5 GTX Series Minimum System Configurations .............................................................................3-4
3.6 Crimping Tools .............................................................................................................................3-4
3.7 Test Equipment .............................................................................................................................3-4
3.8 External Sensors, Devices, and Interface Considerations .............................................................3-5
3.9 Placards/Labels .............................................................................................................................3-7
3.10 Switches ......................................................................................................................................3-7
3.11 Antenna Considerations ..............................................................................................................3-8
3.12 GPS Coaxial Cable Requirements (GTX 335 with SBAS/GPS) ..............................................3-12
3.13 General Installation Practices ....................................................................................................3-13
3.14 Cable and Wiring Considerations .............................................................................................3-13
3.15 General Electrical Bonding .......................................................................................................3-15
3.16 Electrical Load Analysis ...........................................................................................................3-21
4 INSTALLATION PROCEDURE .......................................................................................................4-1
4.1 Structural Installation ....................................................................................................................4-1
4.2 GTX 335 Weight and Balance ....................................................................................................4-10
4.3 Electrical Installation ..................................................................................................................4-11
4.4 GAE and Configuration Module Installation ..............................................................................4-18
4.5 GTX Installation ..........................................................................................................................4-20
4.6 AFMS Completion ......................................................................................................................4-22
5 SOFTWARE UPDATE ........................................................................................................................5-1
5.1 Software Check .............................................................................................................................5-2
6 POST INSTALLATION CONFIGURATION ..................................................................................6-1
6.1 System Configuration Overview ...................................................................................................6-1
6.2 Mounting, Wiring, and Power Checks ..........................................................................................6-1
6.3 GTX 335 Remote Unit Configuration (Wizard Tool) ...................................................................6-2
6.4 GTN 6XX/7XX Configuration with GTX ....................................................................................6-2
6.5 GNS 400W/500W Series Configuration .......................................................................................6-3
7 OPERATION/PERFORMANCE CHECKOUT ...............................................................................7-1

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7.1 Ground Checks - Interfaces (Configuration Mode) ......................................................................7-2
7.2 Ground Checks - Interfaces (Normal Mode) ................................................................................7-3
7.3 Ground Checks - Performance ......................................................................................................7-5
7.4 Documentation Checks .................................................................................................................7-9
8 CONNECTOR PINOUT ......................................................................................................................8-1
8.1 GTX 335 ........................................................................................................................................8-1
APPENDIX A MECHANICAL DRAWINGS .........................................................................................A-1
APPENDIX B INTERCONNECT DRAWINGS .................................................................................... B-1
APPENDIX C EQUIPMENT COMPATIBILITY AND CONFIGURATION ....................................C-1
C.1 Altitude Source ............................................................................................................................ C-2
C.2 Audio Panels ................................................................................................................................ C-4
C.3 TIS-A Traffic Display ................................................................................................................. C-5
C.4 Garmin GTS Traffic Interface Configuration .............................................................................. C-5
C.5 Discrete Configuration ................................................................................................................ C-5
APPENDIX D ACCEPTABLE HARDWARE ........................................................................................D-1

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LIST OF FIGURES
Figure 1-1 GTX 335 Interface Summary ...................................................................................................1-6
Figure 1-2 GTX 335 Front Panel ...............................................................................................................1-7
Figure 1-3 GAE .......................................................................................................................................1-10
Figure 3-1 GPS Antenna Location (GTX 335 with SBAS/GPS) ............................................................3-11
Figure 3-2 Electrical Bond Preparation - Nut Plate .................................................................................3-17
Figure 3-3 Electrical Bond Preparation - Bolt/Nut Joint .........................................................................3-17
Figure 3-4 Electrical Bond Preparation - Terminal Lug ..........................................................................3-17
Figure 3-5 Bonding Strap ........................................................................................................................3-19
Figure 3-6 Transponder Antenna Minimum Ground Plane Radius .........................................................3-20
Figure 3-7 GPS/SBAS Antenna Minimum Ground Plane Radius ..........................................................3-21
Figure 3-8 Ammeter Placement for Current Measurements ....................................................................3-23
Figure 3-9 GTX Electrical Load Tabulation Form ..................................................................................3-25
Figure 3-10 GTX Electrical Load Tabulation Form (Sample) ................................................................3-27
Figure 3-11 Battery Capacity Analysis Example ....................................................................................3-29
Figure 4-1 GTX 335 Installation ...............................................................................................................4-3
Figure 4-2 Panel Cutout Detail for GTX 335 ............................................................................................4-4
Figure 4-3 Avionics Rack Mounting Rail Considerations ........................................................................4-6
Figure 4-4 Fiberglass Insulation for Carbon Fiber Material ......................................................................4-8
Figure 4-5 Aluminum Tape Joint ..............................................................................................................4-8
Figure 4-6 Grounding to Instrument Panel with Aluminum Tape and Grounding Strap ..........................4-9
Figure 4-7 Shielded Wire Preparation .....................................................................................................4-13
Figure 4-8 GTX 335 Connector Kit .........................................................................................................4-16
Figure 4-9 GTX 3X5 with GPS Backplate Assembly P/N 011-02976-01 ..............................................4-17
Figure 4-10 GAE Assembly ....................................................................................................................4-18
Figure 4-11 Configuration Module Assembly .........................................................................................4-19
Figure 5-1 GTX 335 Start-Up Screen ........................................................................................................5-2
Figure 5-2 GTX 335 Product Data Page ....................................................................................................5-2
Figure 6-1 USB-A and USB-B Connectors ...............................................................................................6-2
Figure 7-1 Example EMC Source/Victim Matrix .....................................................................................7-8
Figure 8-1 Rear View, Connector J3251 ...................................................................................................8-1
Figure A-1 GTX 335 Panel Mount Dimensions and Center of Gravity ...................................................A-1
Figure A-2 GTX 3X5 Panel Mount Rack Assembly ................................................................................A-2
Figure A-3 GTX 335 Connector and Vent Location ................................................................................A-3
Figure A-4 Optional Altitude Sensor ........................................................................................................A-3
Figure B-1 GTX 335 - Power, Ground, and Configuration Module Interconnect ................................... B-3
Figure B-2 GTX 335 Switches Interconnect ............................................................................................ B-5
Figure B-3 GTX 335 - GNS 400W/500W Series Interconnect ................................................................ B-6
Figure B-4 GTX 335 - GTN 6XX/7XX Interconnect .............................................................................. B-7
Figure B-5 GTX 335 - Altitude Data Source Interconnect ....................................................................... B-8
Figure B-6 GTX 335 - Audio Interconnect ............................................................................................ B-10
Figure B-7 GTX 335 - GTS 8XX ........................................................................................................... B-11

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LIST OF TABLES
Table 1-1 GTX 335 Unit List ....................................................................................................................1-4
Table 1-2 GTX 335 Pre-Installation Checklist ........................................................................................1-11
Table 1-3 Electrical Load ........................................................................................................................1-12
Table 1-4 Garmin Documents .................................................................................................................1-12
Table 1-5 Garmin Documents Available Upon Request .........................................................................1-12
Table 1-6 Federal Aviation Administration Documents .........................................................................1-13
Table 1-7 Industry Standards ...................................................................................................................1-13
Table 3-1 GTX 335 Connector Kit Options ..............................................................................................3-3
Table 3-2 GTX 335 Backplate Assembly Options ....................................................................................3-3
Table 3-3 GTS 335 Mount Rack Options ..................................................................................................3-3
Table 3-4 GTX 335 Configuration Module ...............................................................................................3-3
Table 3-5 Recommended Crimping Tools ................................................................................................3-4
Table 3-6 Altitude Source Options ............................................................................................................3-5
Table 3-7 Version 2 Compliance w/ Multiple ADS-B Out Equipment Installation ..................................3-7
Table 3-8 Maximum dB loss allowed From Transponder to Antenna ......................................................3-8
Table 3-9 Coaxial Cable Specifications ....................................................................................................3-9
Table 3-10 Typical Cable Connector Loss ................................................................................................3-9
Table 3-11 GTX 335 GPS Antennas .......................................................................................................3-10
Table 3-12 GPS dB Loss Allowance .......................................................................................................3-12
Table 3-13 Ground Plane Definitions and Ground Path Resistance Requirements ...............................3-16
Table 3-14 Airframe Bonding Hardware .................................................................................................3-19
Table 4-1 Instrument Grounding Parts ......................................................................................................4-9
Table 4-2 Weight of GTX Configurations ...............................................................................................4-10
Table 4-3 Example Weight and Balance Calculation ..............................................................................4-10
Table 4-4 Shield Wire Assembly ............................................................................................................4-13
Table 4-5 GTX 335 Connector Kit Hardware .........................................................................................4-16
Table 4-6 Standard Mount Backplate Hardware .....................................................................................4-17
Table 4-7 Configuration Module Kit, P/N 011-00979-03 .......................................................................4-19
Table 8-1 GTX 335 J3251 Pin Assignments .............................................................................................8-2
Table 8-2 Lighting/Power Pin Assignments ..............................................................................................8-4
Table 8-3 GTX 335 Power Control Inputs ................................................................................................8-4
Table 8-4 GTX 335 Encoded Altitude Inputs ............................................................................................8-5
Table 8-5 GTX 335 Discrete Outputs ........................................................................................................8-6
Table 8-6 GTX 335 Discrete Inputs ..........................................................................................................8-6
Table D-1 Screws .....................................................................................................................................D-1
Table D-2 Washer .....................................................................................................................................D-1
Table D-3 Nuts .........................................................................................................................................D-2
Table D-4 Nutplates ..................................................................................................................................D-2
Table D-5 Clipnut .....................................................................................................................................D-2
Table D-6 Rivets .......................................................................................................................................D-2
Table D-7 Rivets, Blind ............................................................................................................................D-2

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1 GENERAL DESCRIPTION
1.1 Introduction.......................................................................................................................................1-2
1.2 Terminology......................................................................................................................................1-2
1.3 Scope.................................................................................................................................................1-4
1.3.1 Approved Aircraft, Systems, and Equipment.............................................................................1-4
1.4 System Overview..............................................................................................................................1-5
1.4.1 GTX 335 Interface .....................................................................................................................1-6
1.4.2 GAE..........................................................................................................................................1-10
1.5 System Installation..........................................................................................................................1-11
1.5.1 Pre-Installation Checklist .........................................................................................................1-11
1.6 Technical Specifications.................................................................................................................1-12
1.6.1 Power Requirements ...............................................................................................................1-12
1.6.2 Environmental Qualification Form ..........................................................................................1-12
1.7 Reference Documentation...............................................................................................................1-12
1.8 STC Permission ..............................................................................................................................1-13

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1.1 Introduction
Install the panel mount GTX 335 with GPS as a minor alteration in accordance with FAA Memorandum
Installation Approval for ADS-B OUT Systems or FAA Notice 8900.362 Policy for Installation of
ADS-B OUT Systems using the data in this installation guidance manual. Installation in accordance with
the FAA Policy Memo only pertains to the GTX 335 with GPS and limited interfaces contained herein.
This installation guidance is comprised of excerpts from the FAA approved GTX 3XX Part 23 AML STC.
If you choose to apply the STC to the aircraft or cover additional interfaces other than the data provided
herein, the panel mount GTX 335 with GPS must be installed in accordance with the complete version of
the Part 23 AML STC installation manual. The additional data must be requested through the Garmin
dealer supplying the equipment.
STC SA01714WI approves a Version 2 (RTCA DO-260B) ADS-B Out compliant solution, meeting
equipment requirements defined in 14 CFR 91.227, using GTX 335 transponders for the Part 23 aircraft
listed on the STC Approved Model List (AML).
Refer to the GTX 33X and GTX 3X5 ADS-B AML STC Equipment List for required hardware and
software configuration.
1.2 Terminology
ADS-B refers to Version 2 ADS-B Out.
References to metallic aircraft in this manual are those with an aluminum skin. Nonmetallic aircraft refers
to all other aircraft (e.g., wooden aircraft, aircraft with composite skin, or aircraft with tube and fabric
construction).
The term squitter refers to a broadcast of aircraft-tracking data that is transmitted periodically by a Mode S
transponder without interrogation from a controller’s radar.
Installation Guidance Abbreviations
AC Advisory Circular
ADC Air Data Computer
ADLP Airborne Data Link Processor
ADS-B Automatic Dependent Surveillance - Broadcast
AFM Airplane Flight Manual
AFMS Airplane Flight Manual Supplement
AHRS Attitude Heading Reference System
AML Approved Model List
ATC Ai r Tr aff i c Co nt ro l
ATC R BS Ai r Tr aff i c Co nt ro l Ra da r Be ac on S ys te m
CFR Code of Federal Regulations
CSA Conflict Situational Awareness
EFIS Electronic Flight Instrument System
EGNOS European Geostationary Navigation Overlay Service
EGPWS Enhanced Ground-Proximity Warning System
ELA Electrical Load Analysis
ELT Emergency Locator Transmitter
EMC Electromagnetic Compatibility

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EMI Electromagnetic Interference
ES Extended Squitter
EQF Environmental Qualification Form
FAA Federal Aviation Administration
FCC Federal Communications Commission
GAE Garmin Altitude Encoder
GDU Garmin Display Unit
GNS Garmin Navigation System
GNSS Global Navigation Satellite System
GPS Global Positioning System
GTN Garmin Touch Navigator
GTX Garmin Transponder
HIRF High Intensity Radio Field
IEL Indirect Effects of Lightning
IM Installation Manual
LRU Line Replaceable Unit
MM Maintenance Manual
OAT Outside Air Temperature
OEM Original Equipment Manufacturer
PED Portable Electronic Device
POH Pilot Operating Handbook
RF Radio Frequency
RTCA Radio Technical Commission for Aeronautics
SBAS Satellite Based Augmentation Systems
SPI Special Position Identification
SRM Structural Repair Manual
STC Supplemental Type Certificate
TAS Traffic Advisory System
TC Type Certificate
TCAS Traffic Alert and Collision Avoidance System
TIS Traffic Information Service
TSO Technical Standard Order
UAT Universal Access Transceiver
USB Universal Serial Bus
WA AS Wi de Ar ea A ug me nt at ion S ys te m

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1.3 Scope
This installation manual provides information for installing a panel mount GTX 335 with GPS unit with
ADS-B Out. Interfaces not required for ADS-B functionality, do not require STC approval such as optional
discrete inputs. These parts are included in this manual as reference only.
All makes and models of airplanes on the AML are applicable. The installer must determine aircraft
applicability before modifying any Type Certified
aircraft to make sure this STC is met.
1.3.1 Approved Aircraft, Systems, and Equipment
This installation guidance manual is applicable to the modification of an aircraft in the
Part 23 AML STC SA01714WI to install the equipment in table 1-1.
Table 1-1 GTX 335 Unit List
Unit Description P/N
GTX 335 GPS Black front, panel mounted, extended squitter with internal
GPS
source 011-03300-40
GAE Altitude Encoder, Garmin (GAE) 011-03080-00

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1.4 System Overview
ADS-B technology improves situational awareness and flight safety. A Garmin transponder with ADS-B
Out functions automatically transmit position, velocity, and heading information to other aircraft and
ground stations. The air traffic control system uses transponder requests for appropriate aircraft
information. ADS-B Out gives automatic transmission of aircraft information without a request.
The GTX 335 transponders have an optional Garmin
Altitude Encoder (GAE) to meet the required
barometric pressure altitude source and the internal
GPS/SBAS source that meets the required GNSS
position source integrity for ADS-B Out.
The GTX 335 transponders have a radio transmitter/receiver that operates on L-Band
radio frequencies.
These transponders receive ground radar or TCAS interrogations and transmit a coded
response of pulses to
ground based radar on a frequency of 1090 MHz. Each unit has IDENT capability
and replies to ATCRBS
Mode A, Mode C, and Mode S All-Call interrogations.
Consider the following if installing a GTX 335 in an aircraft with an existing ADS-B Out source.
1. Current FAA guidance allows multiple ADS-B Out transmissions on both links if the ICAO
aircraft
identifier is provided on both systems.
2. Garmin recommends all ADS-B out systems be fully compliant at the time the aircraft is equipped
with any fully complaint ADS-B out system. This can be accomplished by either disabling the
earlier version of ADS-B out, or upgrading it to also meet full compliance requirements. Refer to
section 3 for additional details.

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1.4.1 GTX 335 Interface
The GTX 335 units are panel mounted units that have Mode S with ADS-B Out extended
squitter capability.
The GTX 335 units contain an integrated display for normal operation and functionality. It is recommended
to wire
uninterrupted aircraft battery power to the GPS keep alive input for the GTX 335 with SBAS/GPS
receivers. This preserves internal SBAS/GPS data between unit power cycles and minimizes the time
required to obtain an initial position fix.
GTX 335 features:
Mode S transponder
ADS-B Out capability
Internal GNSS receiver
Optional GAE pressure sensor module
Entry of squawk code and flight ID
Show squawk code and flight ID
Show pressure altitude
Show outside air temp
Show density altitude
Show flight timers
Audio output
TIS-A traffic output to a compatible display
The transponder provides an ADS-B Out failure message to alert that the unit has a degraded ADS-B
system. Refer to
figure 1-1 for GTX 335 interfaces.
Figure 1-1 GTX 335 Interface Summary
The following provides detail regarding the panel function of the GTX 335. Refer to GTX 3X5 Pilot's Guide
or GTX 33X and GTX 3X5 ADS-B Maintenance Manual for
more information about the controls and their
functions.
GTX 335
GPS Antenna
Audio Panel
Bottom Antenna
Power/Ground
Altitude Source
2
nd
Air Data Source
Existing LRUNew LRU
Legend
Optional Interfaces Required Interfaces
Squat Switch
Garmin Altitude
Encoder
OR
Temperature
External Ident
Keep Alive Input

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Figure 1-2 GTX 335 Front Panel
NOTE
If the transponder is in the ON or ALT operating mode, the transponder becomes an active
part of the Air Traffic Control Radar Beacon System (ATCRBS). The transponder will reply
to interrogations from aircraft with TCAS installed.
Key Selection Functions for GTX 335:
OFF Turn off the GTX 335.
SBY Selects the Standby mode. Push the STBY key when the GTX 335 is
powered off to automatically energize the unit on in standby mode. When
in
standby mode, the transponder does not reply to any interrogations but
new
codes can be put in and a SBY indication will show on the display.
ON Selects the On mode, which gives Mode A and Mode S replies, but Mode
C
altitude reporting is prevented. Push the ON key when the GTX 335 is
powered off to automatically energize the unit in Mode A, and transmit a
squawk code when interrogated. ADS-B Out will not return barometric
altitude as it switches to GPS altitude while in this mode. Interrogations
are
shown by the reply symbol (R). For On mode, the replies do not
include
altitude information.
ALT Altitude mode is automatically selected when the aircraft becomes
airborne,
using the units air/ground logic, or when the ALT key is pushed.
Push the ALT key when the GTX 335 is powered off to automatically
energize the unit in altitude reporting mode. While the aircraft is on the
ground and in ALT mode, the transponder does not give Mode A and
Mode C
replies, but it does give acquisition squitter and replies to
discretely addressed
Mode S interrogations.
While the aircraft is in ALT mode and airborne it will give Mode A,
Mode C,
and Mode S replies and give transmissions of acquisition and
extended
squitter, to include ADS-B Out.
All transponder interrogation replies are shown by the Reply symbol (R).
VFR Sets the transponder code to the pre-programmed VFR code
selected in
Configuration mode (set to 1200 at the factory). Push the

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VFR key again to restore the identification code used before.
FUNC In normal mode, push the FUNC key to change the subpage group shown
on
the right side of the display. Sub-pages include: Flight ID, Pressure
Altitude,
Flight Time, Altitude Monitor, System Count Up, and Count
Down Timers. In
the Configuration mode, moves through the function
pages.
ENT Accepts entry for selected item and moves the cursor to the next
changeable
item, or function selection, in configuration and normal
operation. Starts and
stops the Altitude Monitor, Count Up, Count Down,
and Flight timers.
CRSR Selects changeable fields in configuration and normal operation. Starts
entry
of the start time for the Count Down timer and cancels transponder
code entry.
Hold the CRSR key to put the unit into a Ground Test mode
that forces the
aircraft into an airborne status for tests.
CLR Resets the Count Up, Count Down, and Flight timers. Cancels the key
pushed
before during code selection, Count Down entry, or flight ID
entry. Used in
Configuration mode to scroll through the function pages.
8Used as a scroll-up key to move through page groups in normal and
configuration mode.
9Used as a scroll-down key to move through page groups in normal and
configuration mode.
Display Functions:
FLIGHT ID If the system is configured to ALLOW PILOT TO EDIT FLT ID in
configuration mode to YES, the FLIGHT ID can be changed by the pilot
at
any time in normal mode. This lets the pilot/crew to put in the specific
Flight
ID for transmission to ATC interrogations.
UP COUNTER Timer controlled by ENT and CLR keys.
DOWN COUNTER Timer controlled by ENT, CLR, and CRSR keys. The initial Count
Down
time is put in with the 0- 9 keys.
FLIGHT TIMER Shows the Flight Time, controlled by the ENT key or by one of four
airborne
sources (squat switch, GPS ground speed recognition, air data
airspeed
recognition or altitude increase) as configured during
installation. The timer
starts when the GTX 335 finds that the aircraft is
airborne.
TRIP TIMER Timer controlled by ENT and CLR keys.
PRESSURE ALT Shows the altitude data supplied to the GTX 335 in feet, hundreds of
feet
(i.e., flight level), or meters, selected at configuration.
ALT MONITOR Controlled by ENT key. Operates a voice alarm and warning
annunciator
when above altitude limit.

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SAT/DALT Shows when the GTX 335 is configured with temperature input. Shows Static
Air Temperature and Density Altitude.
CONTRAST/OFFSET Contrast is controlled by the 8 and 9 keys.
BACKLIGHT/OFFSET This page is displays when photocell backlighting mode is selected in
Configuration mode. Backlighting is controlled by the 8 and 9 keys.
MESSAGES Alerts user of transponder faults, fails and advisory messages. MSG displays
when a message is generated. CRSR and ENT keys access messages
to view
and acknowledgment.
1090ES TX CTRL This is only shown when the unit is configured for 1090ES OUT CONTROL
in Configuration mode to be PILOT SET. When configured, this can be
highlighted by the CRSR key, changed by the 8 and 9 keys, and selected by
ENT key. Sets the extended squitter function on or off.

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1.4.2 GAE
The GAE module supplies the required barometric altitude source for ADS-B Out compliance. The sensor
module has an orifice that allows the module to be connected to the static system. The GAE attaches to the
rear connector plate with two screws, and has short, unshielded wires to connect to the GTX 335 unit
through the rear D-sub connector with the same connection as the configuration module. The GAE contains
the configuration module. If the GAE is used, a separate configuration module is not required. Refer to
section 4 for installation guidance.
Figure 1-3 GAE


190-00734-17 GTX 335 w/GPS Installation Guidance
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1.5 System Installation
This section gives equipment information to install the GTX system and related hardware. For interconnect
diagrams, refer to section B.
1.5.1 Pre-Installation Checklist
Before beginning a GTX system installation the installer must make sure the aircraft meets the prerequisites
for the installation of the GTX system under this STC. Use the checklists from table 1-2 to determine the
necessary requirements that must be met before the installation of the GTX is started in a specific aircraft.
Make sure each of the items are completed as necessary before modifying.
Table 1-2 GTX 335 Pre-Installation Checklist
Prerequisite Reference GTX 335
with GPS Complete
Aircraft is on AML AML  
Approved uncorrected pressure altitude
source or GAE option installed Appendix C  
Satisfactory SBAS/GPS antenna installed Appendix C  
Satisfactory transponder antenna installed Section 3.11  
Satisfactory attachment provisions have
been identified
 
Satisfactory electrical bonding provisions
have been identified Section 3.15  
Planned equipment interfaces are
approved under the STC or have other
FAA approval
Appendix C  
Installation/operational limitations
reviewed to make sure no adverse impact
to installation
Section 2  
Aircraft electrical system is sufficient for
the installation Section 3.16  
Aircraft does not have a TCAS II system Section 2  

190-00734-17 GTX 335 w/GPS Installation Guidance
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1.6 Technical Specifications
1.6.1 Power Requirements
The GTX 335 units operate at 14 or 28 VDC. Refer to table 1-3 for electrical load lists current draw
specifications.
Table 1-3 Electrical Load
1.6.2 Environmental Qualification Form
The installer must obtain the latest revision of the GTX Environmental Qualification Form (EQF). A copy
of the EQF is obtained through the single-use registration code process. For the applicable GTX EQF part
number, refer to table 1-4.
1.7 Reference Documentation
Table 1-4 Garmin Documents
Table 1-5 Garmin Documents Available Upon Request
Unit Characteristic
Specification
14 VDC 28 VDC
GTX 335 w/ GPS
Input current, typical 0.72 A 0.36 A
Input current, maximum 1.22 A 0.61 A
GTX 335 w/ GPS KEEP ALIVE input current
65 µA typical 20 µA typical
85 µA maximum 40 µA maximum
Document P/N
GTX 3X5 Environmental Qualification Form 005-00752-02
GTX 335 Setup Wizard Guide 190-01499-40
Master Drawing List, GTX 33X and GTX 3X5 ADS-B AML STC 005-00734-04
GTX 33X and GTX 3X5 ADS-B AML STC Equipment List 005-00734-05
GTX 33X and GTX 3X5 ADS-B Maintenance Manual 190-00734-11
AFMS, GTX 33X and GTX 3X5 AML STC 190-00734-15
GTX 3X5 Series Transponder Pilot’s Guide 190-01499-00
Document P/N
GTX 3XX Part 23 AML STC Installation Manual 190-00734-10
GTX 3X5 TSO Installation Manual 190-01499-02